1/*
2 * Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
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23 */
24
25#ifndef SHARE_UTILITIES_GLOBALCOUNTER_INLINE_HPP
26#define SHARE_UTILITIES_GLOBALCOUNTER_INLINE_HPP
27
28#include "runtime/atomic.hpp"
29#include "runtime/orderAccess.hpp"
30#include "runtime/thread.inline.hpp"
31#include "utilities/globalCounter.hpp"
32
33inline GlobalCounter::CSContext
34GlobalCounter::critical_section_begin(Thread *thread) {
35 assert(thread == Thread::current(), "must be current thread");
36 uintx old_cnt = Atomic::load(thread->get_rcu_counter());
37 // Retain the old counter value if already active, e.g. nested.
38 // Otherwise, set the counter to the current version + active bit.
39 uintx new_cnt = old_cnt;
40 if ((new_cnt & COUNTER_ACTIVE) == 0) {
41 new_cnt = Atomic::load(&_global_counter._counter) | COUNTER_ACTIVE;
42 }
43 OrderAccess::release_store_fence(thread->get_rcu_counter(), new_cnt);
44 return static_cast<CSContext>(old_cnt);
45}
46
47inline void
48GlobalCounter::critical_section_end(Thread *thread, CSContext context) {
49 assert(thread == Thread::current(), "must be current thread");
50 assert((*thread->get_rcu_counter() & COUNTER_ACTIVE) == COUNTER_ACTIVE, "must be in critical section");
51 // Restore the counter value from before the associated begin.
52 OrderAccess::release_store(thread->get_rcu_counter(),
53 static_cast<uintx>(context));
54}
55
56class GlobalCounter::CriticalSection {
57 private:
58 Thread* _thread;
59 CSContext _context;
60 public:
61 inline CriticalSection(Thread* thread) :
62 _thread(thread),
63 _context(GlobalCounter::critical_section_begin(_thread))
64 {}
65
66 inline ~CriticalSection() {
67 GlobalCounter::critical_section_end(_thread, _context);
68 }
69};
70
71#endif // SHARE_UTILITIES_GLOBALCOUNTER_INLINE_HPP
72